Fusel Production/Reduction

[VikeMan]

I haven't really had any problems with fusel alcohols, but sometimes I just wonder about things. Anyone know a good technical reference about how they are produced and then reduced?

I have read (in various forum posts) that fusel production is usually caused by higher fermentation temps. But I'm actually more curious about their reduction. I've heard that both of the following will reduce their levels...

1) 'Time'
2) Combination with fatty acids to form esters

Are either/both of the above true? If so, at what temperatures? And is yeast activity involved in their reduction? TIA!

 

[kansasbrew]

Time might actually work against you during the fermentation. Palmer seems to suggest that too long on trub can account for fusel production. http://www.howtobrew.com/section4/chapter21-2.html
Maybe a longer time in the secondary or during bottle conditioning, but maybe someone else can answer that.

 

[cox8611]

I want to say that there's a third way to produce fusel alcohols... and its just by experience...

3) Stressed yeast from underpitching in a high OG environment

Had a tripel that fermented high/ WAY underpitched back in august that STILL tastes and smells like rubbing alcohol.

 

[devilishprune]

I have a couple of pdf articles that you may be interested in. If you PM me your email address then I can send them to you if you would like.

Something else that effects fusel formation that hasn't been mentioned is pressure. Fermenting under increased pressure reduces the amount of fusels and esters produced during fermentation.

Higher pitching rates don't really lower fusel production as much as you would think, based on an article that I've read.